<template>
  <div class="hello">
    <h1>{{ msg }}</h1>
    <hr />
    <input type="text" v-model="firstName" />
    <div>firstName:{{ firstName }}</div>
    <input type="text" v-model="lastName" />
    <div>lastName:{{ lastName }}</div>
    <div>fullName:{{ fullName }}</div>
  </div>
</template>

<script>
import { ref, watch } from "vue";
export default {
  name: "HelloWorld",
  props: {
    msg: String,
  },
  setup() {
    const firstName = ref("尼古拉斯");
    const lastName = ref("赵四");
    const fullName = ref("");
    // 监听
    watch(
      firstName,
      (nval, oval) => {
        fullName.value = nval + "-" + lastName.value;
      },
      { immediate: true, deep: true }
    );
    watch(
      lastName,
      (nval, oval) => {
        fullName.value = firstName.value + "-" + nval;
      },
      { immediate: true, deep: true }
    );
    return {
      firstName,
      lastName,
      fullName,
    };
  },
};
</script>


<style scoped>
</style>
